A.] FORBES AND RENDU. 523 



2. Professor TyndalVs General Account of EeiuliCs 'TMorie des 



Glacitrs.' 



In the course of these few pages, Professor Tyndall conveys 

 to his reader the apprehension that the memoir of Monseigneur 

 Hi- mlu on the Glaciers of Savoy has been almost entirely over- 

 looked by English writers and readers on this subject : that the 

 descriptions of it have been inaccurate and even deceptive, the 

 extracts partial and not characteristic, so that when, after several 



- of study of the science of glaciers, his own attention was 

 distinctly called by a Swiss friend to Bishop Eendu's work, 1 he 

 was surprised to find evidence of extensive knowledge, close and 

 accurate reasoning, and an extraordinary faculty of observation ; 

 together with a constant effort after quantitative accuracy, and 

 ' a presentiment concerning things as yet untouched by experi- 

 ment which belongs only to the higher class of minds.' 2 Nor 



he less struck to find that the memoir contained passages of 

 'cardinal import' which previous writers had 'overlooked,' and 

 that it should devolve on himself to call attention to them 

 ' nearly twenty years after their publication.' 



Whether these merits of Bishop Rendu had really been over- 

 looked, as is here supposed how far the statements of ' cardinal 

 import' referred to had been knowingly or otherwise allowed to 



into forgetfulness, and required to be revived after twenty 



tf oblivion I will presently endeavour to show. But I must 

 first state why I feel my credit involved in these allegations, so 

 as to induce ine to withdraw from the neutral attitude which I 

 have generally adopted towards Professor Tyndall's criticisms. 



reasons of my present remonstrance are these : 

 .< That though the allegation that Bishop Rendu's Theory 

 has been undervalued, or represented only by insufficient and 

 partial extracts from his writings, is for the most part made in 



ral terms, 8 yet it is to be inferred from the entire section 



7 am the writer most to blame. Moreover, at page 304 



of his work, Professor Tyndall, after quoting a passage from 



lu, states that it enables him to correct a 'grave iiiisappiv- 



1 Sec Phil. Tran*., 1859, p. 271. * Glaciers of the Alps, p. 299. 



* A*, for example, in the following note : ' In all that has been written upon 

 glaciers in this country, the above passages from the writings of Rendu arc un- 

 quoted ; and many who mingled very warmly in the discussions of the subject 

 until nuite recently, ignorant of their existence. I was long in this con- 

 dition myself, for I never supoosed that passages which bear so directly upon a 

 jM.int so much discussed, ana of such cardinal import, could have been o\< T- 

 looked ; or that the task of calling attention to them should devohe, upon 

 myself nearly twenty years after their publication. Now that they are dis- 

 covered, 1 conceive no difference of opinion can exist as to the propriety of 

 .in in their true position.' TrtiDALL's Glaciers of tht Alps, 



